1. Field of the Invention
The present invention relates to a valve assembly, and more specifically, a valve assembly for controlling pressures on opposing sides of the valve assembly prior to opening the valve assembly.
2. Description of the Related Art
Valve assemblies are used for regulating flow in a fluid pipeline system. These valve assemblies comprise a housing having a first chamber, a second chamber, and a valve seat disposed between the first and second chambers. A valve head is disposed in the housing and is moveable relative to the housing between an open position spaced from the valve seat and a closed position engaged with the valve seat.
Valve assemblies are commonly used in a fluid pipeline system having a bidirectional flow. When the valve head is in the closed position, the fluid can exert a pressure against a front portion and/or a back portion of the valve head to create a pressure differential between the front and back portions. In one instance, when a pressure exerted on the back portion is greater than that on the front portion, the pressure on the back portion presses the valve head toward the closed position and impedes the movement of the valve head to the open position. Additionally, the pressure on the back portion may become great enough to cause damage to one or more elements of valve assembly and/or the fluid pipeline system. It would be desirable to have a valve capable of equalizing the pressure between the front and back portions of the valve head or otherwise relieving pressure build-up at the valve head.
In addition, valve assemblies of the prior art have internal components or structure that cause flow restrictions that interfere with the fluid flow. This interference can produce energy loss as fluid flows from an inlet to outlet of the valve assembly thereby decreasing fluid flow performance. It would be desirable to reduce flow restrictions to increase the flow through the valve assembly.